[Sensitivity of hypothalamic neurons to beta-endomorphin, met-enkephalin, and thyroliberin]

A study was made of susceptibility of hypothalamic neurons to beta-endorphine, thyroliberin and met-enkephalin applied microiontophoretically. The opioids were shown to exert a primarily unidirectional effect on the same neurons irrespective of the fact that the inhibitory action of beta-endorphine was more pronounced. The nalorphine-competitive antagonist of the opiates removed the met-enkephalin-induced inhibition. Unlike opioids, thyroliberin largely activated the test neurons. The possibility of neuropeptide participation in the control of gonadotropic function of the pituitary is discussed.